"It was a David and Goliath moment"

When world renowned photographer Stuart Franklin was standing on a crowded balcony five stories up from Beijing's Tiananmen Square, pointing his camera at a man standing defiant in front of a row of Chinese tanks, he thought he was too far away from the action.

But 25 years after that iconic day on 5 June 1989, the picture has become the ultimate symbol of the power of an individual against the might of the state.